Improvement in asphaltic pavements



UNITED Snares or both; also some ATENT FFIOE.

SAMUEL R. SGHARF, OF BALTIMORE, MARYLAND, ASSIGNOR TO HIMSELF AND HUGHM. FUNSTON, OF NEW YORK.

* meaovswisar IN ASPHALTlC PAVEMENTS.

Specification forming part of Let ers Patent No. l I 1,151. datedJanuary 24, le'il.

- To all whom; it may concern:

Be it known that I, SAMUEL R. Sonnan, of Baltimore, in the State ofMaryland,have invented a new and useful Improvement in AsphalticPavement for Streets and Carriageways; and I hereby declare that thefollowing is a full description thereof: v

My invention consists of an improved asphaltic pavement and of a new andpeculiar materials and method of arrangement of the making the same as awhole; and, secondly,

I in the use of a stifi bitumen, without coal-tar,

in the base or bottom layer ofa stone and asphalt pavement.

indestructible materials are wet with this inixture while hot, and thena layer of from four to seven inches put down and rolled with a rollerweighing about one ton. Next Lput down a layer, say from one to twoinches, of'

broken stone, which is heated and then mixed with a hot mixture ofbitumen and asphalt, in.

'- the proportion of one gallon of bitumen to one-half, pound ofasphalt. This layer is first rolled with a light roller, and then with aroller weighing about four tons. After this Iput on a layer, say one ortwoinches thick, of a stone or fine gravel, carbonate of linie or by.draulic cement, all thoroughly mixed and wet mixture of finely-brokenwith the above-described, mixture of bitumen and asphalt. The mixture. oflpitumen and asphalt and also the other materials are first heatedbefore mixing and laid down hot. This layer is course or layer. As afinishing course I spread ":2'. The use of tar, in the base of anasphalt and stone pave.

thoroughlyirolled' like the second on some dust or carbonate of lime,and again roll thoroughly.

In some cases or climates the asphalt, carbonate of lime, and cement mayin whole or in' part be omitted. By using coal-tar bitumen in the base,the stones are held firmly in p place used. Thus I make a solidfoundation. The

and will not work as when coal-tar is heavy oil which is added to thebase serves as a reservoir to replace'slight evaporation from thesurface, and thus prese'rves the life of the pavement, or prevents itfrom becoming brittle. The asphalt in the second and higher coatsobviates thesoftening effects of the sun in summer. The carbonate oflime 'orhydraulic cement will retard or almost entirely prevent theevaporation of the heavy oil yet remaining in the bitumen; and,consequently,-preserves the life of the material, as alreadymentioned.The bitumen which I use'is made by distilling coal-tar over a slow fire,the distillation being continued as long as possiblewith out burning. orrendering'the bitumen brittle when cold. I Having thus described myinvention, I

claimwhole, the same having first a base of stones. mixed with and laidin stifl'bitumen, (obtained from long-distillation of coal-tam) and thenwell rolled; second, a layer of smaller stones coated witha mixture ofbitumen and asphalt, also rolled; third, a

layer of-- fine gravel or broken stone wet with said m1xture,likewiserolled and finally,covered*with, carbonate of a lime orwater cement, andfinished 'by rolling, substantially as set forth.

stifl. bitumen, without coalment,.substantially as described;

Witnesses: SAML.'R.-SCHARF.

DANIEL BREED, 7

EDM. F. BROWN;

1. The" above described pavement as a V

